How do you Add or Update a JProperty Value in a JObject

I am currently using the following extension method to perform this task, but it almost seems like there should be some existing included method or extension to perform this (or at least a subset of this). If there isn't anything within Json.NET then what is the recommended process, or how would I change the code below to be closer to the recommended process.

public static partial class ExtensionMethods
{
    public static JObject SetPropertyContent(this JObject source, string name, object content)
    {
        var prop = source.Property(name);

        if (prop == null)
        {
            prop = new JProperty(name, content);

            source.Add(prop);
        }
        else
        {
            prop.Value = JContainer.FromObject(content);
        }

        return source;
    }
}

I can confirm the above code works for basic usage, but I'm not certain how well it holds up to broader usage.

The reason I have this extension returning a JObject is so that you would be able to chain calls (either multiple calls to this extension or to other methods and extensions).

i.e.,

var data = JObject.Parse("{ 'str1': 'test1' }");

data
    .SetPropertyContent("str1", "test2")
    .SetPropertyContent("str3", "test3");

// {
//   "str1": "test2",
//   "str3": "test3"
// }

as @dbc described in the comment, you can simply use the indexer to make this happen.

var item = JObject.Parse("{ 'str1': 'test1' }");

item["str1"] = "test2";
item["str3"] = "test3";

see the fiddle for more details

Anyone trying to access nested JSON use the approach as in answer by @pjs adding extra braces as required.

JObject item = JObject.Parse("{
   "test": {
       "first": "one",
       "second": "two",
       "nth":   "n"
   }
}");

To edit:

item["test"]["nth"] = "updated";

Updates the JObject to:

{
   "test": {
       "first": "one",
       "second": "two",
       "nth":   "updated"
   }
}